The "Find all" function seems to be ideal for a small document, because the
highlight will not be effective if the matches are far from each other in a long
document. (In such cases, the "Find next" would be useful.)

But both these modes fall short of expectation if the user wants to rapidly
navigate through the matches. 

In other words, if he wants to have random access to all the matching strings,
especially in large documents, the existing mechanisms are not suitable.

Suggestion: Show all results in a pane, as a list. Show the text surrounding the
matching string (as Acrobat Reader shows). The user can then click on any entry
to jump there. He can check out multiple entries rapidly, in any random order
across the document. 

The list should remain open till he closes it.